Mendez, who hailed from Tepalcatepec in Michoacán state, by the late 1990s already was working for organised drug rings shipping cocaine and marijuana to the United States, a report by the US Drug Enforcement Administration.

The stocky Mendez had been in a major internal conflict over a group that split from La Familia – dubbed the Knights Templar, who are led by Servando Gomez alias "La Tuta." The Knights have been blamed for a spectacular surge in deadly crime in Michoacán in recent months.

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Earlier, President Felipe Calderón sent a message on his personal Twitter account, saying: "A great blow by federal police against organised crime. One of the most wanted criminals captured. Congratulations."

La Familia is one of Mexico's most violent drug cartels, and its stronghold is in Michoacán state where it has been battling the Los Zetas gang.

The former head of La Familia, Nazario Moreno, was killed in December in a shoot-out with police. Classed among Mexico's seven major drug cartels, La Familia is considered the country's top producer of synthetic drugs and has always had its heart in Michoacán.

The state on the Pacific coast happens to be a big producer of marijuana, opium poppies and Calderon's home state.

La Familia announced its arrival on the scene in October 2006, when its men walked into a bar and rolled five severed heads onto a dance floor.

The gang was soon posing a direct challenge to the federal government, killing eight people in a grenade attack on a crowd celebrating Mexico's independence day on September 15, 2008.

In July 2009, it killed 16 police officers, 12 of whom were found in a heap on the side of a road.

The toll in suspected drug-related violence in Mexico has surpassed 37,000 since Calderón launched a military crackdown on organised crime in 2006.

Since 2006, authorities have killed or arrested several top cartel leaders, including Arturo Beltran Leyva, head of the cartel bearing his name, in December 2009; and Gulf cartel chief Ezequiel Cárdenas Guillen, alias "Tony Tormenta."